1. Field of the Invention
This invention concerns fibers of narrow cross section composed of cellulose acetate and suitable for tobacco smoke filters.
2. Description of the Prior Art
It is well-known that tobacco smoke contains aldehydes such as acetaldehyde, formaldehyde and acrolein, ketones such as acetone, phenolic compounds, alkaloids such as nicotine, organic acids and those materials referred to as tars such as benzopyrene. Tobacco smoke has undesirable effects on smokers' lungs, livers, kidneys and stomachs and, accordingly, it is not good for the smokers' health.
Although there have been various attempts for removing these ingredients, for instance, use of tobacco filters, their effects have not yet been quite satisfactory. That is, conventional tobacco smoke filters comprise tows of cellulose acetate fibers and the cross sectional shape of the filter fibers have progressed from that of the blossom shape referred to as a regular cross section and prepared by spinning through a circular nozzle, into the letter I-cross sectional shape or the letter Y-cross sectional shape, but there have not yet been actually provided tobacco smoke filters that give effective air permeation resistance with a small fiber filling rate and give a satisfactory tar/nicotine removing rate.